lpc176x: Move enable_peripheral_clock to main.c

Move and rename function to enable_pclock() - in keeping with other
ARM ports.

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>

src/lpc176x/spi.c

@@ -24,7 +24,7 @@ spi_init(void)
     gpio_peripheral(0, 18, 2, 0);
 
     // Setup clock
-    enable_peripheral_clock(PCLK_SSP0);
+    enable_pclock(PCLK_SSP0);
 
     // Set initial registers
     LPC_SSP0->CR0 = 0x07;